How Patrick Wardle Hid a Backdoor in His High School Calculator

Years before he became the world’s most well known MacOS hacker, Patrick Wardle was a high school nerd curious about hacking. His first hack was figuring out that he could program his fancy calculator and hide a backdoor in it that could help him with his calculus tests. His teacher never caught him, and he actually learned how to solve calculus equations by programming his calculator. “So I’m sure that in retrospect my calculus teacher would be stoked...or that’s what I tell myself,” Wardle said.

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Damn, I used to program mole conversions into my TI83 to uh… help… in my chemistry tests. Should have kept up that train of thought and been a cool hacker. C’est la vie.


I found it weird that many math classes I took required us to have specific brands of calculator that were very programmable and sometimes didn’t even explicitly tell us not to program them to solve the kinds of problems we knew we’d be seeing on tests. ¯\_(ツ)_/¯


I swear my statistics teacher was doing this on purpose, because he taught us in class how to make a program for every type of question we would encounter on the test… but then told us not to use them for the actual test?

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Pretty sure my high school algebra and geometry teachers actively encouraged us to program our TI-83s to solve various formulas because they figured we’d learn the formulas better that way.

Also reminding me of a very, very silly rule the SATs (used to?) have where calculators with QWERTY keyboards were banned but an ABCDEF keyboard was apparently fine, so I was able to bring a fully programmable CAS calculator that I could type and save notes on into that test on a technicality. Like this was one of those calculators you could emulate 3rd gen Pokemon games on. So uh, if you needed any more indication that standardized tests are bullshit, there’s that.


Never did learn to program my TI 83 in high school. Did spend a lot of time in maths class playing The Urinal Game:

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I loved my TI-84! So much time spent with it in highschool and college. I get that a phone can do a lot of what it can but there is something real good feeling about a giant solid calculator. I got mine out last month and discovered it was completely dead even with brand new batteries. Not going to lie I was looking at those fancy nspires and trying to justify the purchase.

My engineer dad would take away my TI-83 whenever I was doing homework, saying that no kid of his is going to learn math with a computer. He only bought one because it was explicitly in the class syllabus, but it did it make my math knowledge stronger for not using it.

It’s funny, sometimes I had to tell him “I’m using it to play Tetris, honest!” just so he’d let me hang on to it.

I bought a TI-83 for school several years back and took it with me when I moved because it was like an 80 something dollar purchase. The batteries died, but I’m not sure if it still works. I have a lot of trauma around math as a subject, so much so that I phased myself out of a degree in Education to keep from passing it on, so it’s safe to say I’ll never use it again. I’ll probably check to see if it works and give it away to someone who needs it if it does. It’s nice to see other people getting better use out of these things than I ever did.